INVESTMENTS (Details 4) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011 Reclassification of debt securities from held-to-maturity to trading account assets	Dec. 31, 2008 Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Mortgage-backed securities	Dec. 31, 2011 Mortgage-backed securities	Mar. 31, 2011 Mortgage-backed securities Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Prime	Dec. 31, 2011 Prime	Mar. 31, 2011 Prime Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Alt-A	Dec. 31, 2011 Alt-A	Mar. 31, 2011 Alt-A Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Subprime	Dec. 31, 2011 Subprime	Mar. 31, 2011 Subprime Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Non-U.S. residential	Dec. 31, 2011 Non-U.S. residential	Mar. 31, 2011 Non-U.S. residential Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Commercial	Dec. 31, 2011 Commercial	Mar. 31, 2011 Commercial Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 State and municipal securities	Dec. 31, 2011 State and municipal securities	Mar. 31, 2011 State and municipal securities Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Corporate	Dec. 31, 2011 Corporate	Mar. 31, 2011 Corporate Reclassification of debt securities from held-to-maturity to trading account assets	Mar. 31, 2012 Asset-backed securities	Dec. 31, 2011 Asset-backed securities	Mar. 31, 2011 Asset-backed securities Reclassification of debt securities from held-to-maturity to trading account assets
Schedule of Held-to-maturity Securities
Investment reclassified from investments held-to-maturity to trading account assets			$ 10,000,000,000
Investment reclassified from investments held-to-maturity to trading account assets subsequently sold substantially			12,700,000,000
Investments held-to-maturity sold			2,700,000,000
Net pretax loss recognized in the consolidated statement of income			(709,000,000)
After tax loss recognized in the consolidated statement of income			(427,000,000)
Gross unrealized gains included in other revenue			311,000,000
Gross unrealized losses included in other-than-temporary-impairment losses on investments			1,387,000,000
Net realized gains included in realized gains (losses) on sales of investments			367,000,000
After tax unrealized losses reflected in AOCI			1,012,000,000
Debt Securities Held-to-maturity
Amortized cost	12,224,000,000	13,759,000,000	14,366,000,000		8,670,000,000	9,475,000,000	9,441,000,000	341,000,000	360,000,000	3,410,000,000	4,117,000,000	4,732,000,000	5,357,000,000	274,000,000	383,000,000	240,000,000	3,446,000,000	3,487,000,000	317,000,000	492,000,000	513,000,000	117,000,000	1,377,000,000	1,422,000,000	900,000,000	1,201,000,000	1,862,000,000	3,569,000,000	976,000,000	1,000,000,000	456,000,000
Net unrealized loss recognized in AOCI	2,098,000,000	2,276,000,000	1,656,000,000		1,847,000,000	2,045,000,000	1,524,000,000	61,000,000	73,000,000	528,000,000	1,241,000,000	1,404,000,000	896,000,000	44,000,000	47,000,000	7,000,000	499,000,000	520,000,000	75,000,000	2,000,000	1,000,000	18,000,000	91,000,000	95,000,000	8,000,000	127,000,000	113,000,000	115,000,000	33,000,000	23,000,000	9,000,000
Carrying value	10,126,000,000	11,483,000,000	12,710,000,000		6,823,000,000	7,430,000,000	7,917,000,000	280,000,000	287,000,000	2,882,000,000	2,876,000,000	3,328,000,000	4,461,000,000	230,000,000	336,000,000	233,000,000	2,947,000,000	2,967,000,000	242,000,000	490,000,000	512,000,000	99,000,000	1,286,000,000	1,327,000,000	892,000,000	1,074,000,000	1,749,000,000	3,454,000,000	943,000,000	977,000,000	447,000,000
Gross unrecognized gains	210,000,000	182,000,000	1,353,000,000		103,000,000	105,000,000	839,000,000	22,000,000	21,000,000	131,000,000	2,000,000	20,000,000	605,000,000	1,000,000	1,000,000	5,000,000	72,000,000	59,000,000	76,000,000	6,000,000	4,000,000	22,000,000	90,000,000	68,000,000	68,000,000	8,000,000		396,000,000	9,000,000	9,000,000	50,000,000
Gross unrecognized losses	680,000,000	1,165,000,000	407,000,000		535,000,000	752,000,000	357,000,000	7,000,000	20,000,000	131,000,000	237,000,000	319,000,000	188,000,000	37,000,000	71,000,000	36,000,000	224,000,000	290,000,000	2,000,000	30,000,000	52,000,000		70,000,000	72,000,000	7,000,000	1,000,000	254,000,000	41,000,000	74,000,000	87,000,000	2,000,000
Fair value	9,656,000,000	10,500,000,000	13,656,000,000		6,391,000,000	6,783,000,000	8,399,000,000	295,000,000	288,000,000	2,882,000,000	2,641,000,000	3,029,000,000	4,878,000,000	194,000,000	266,000,000	202,000,000	2,795,000,000	2,736,000,000	316,000,000	466,000,000	464,000,000	121,000,000	1,306,000,000	1,323,000,000	953,000,000	1,081,000,000	1,495,000,000	3,809,000,000	878,000,000	899,000,000	495,000,000
Net unrealized losses recorded in AOCI and excluded from gross unrecognized losses	2,100,000,000	2,300,000,000
Debt securities transferred from trading account assets to investments held-to-maturity				6,647,000,000
Debt securities transferred from Investments available-for-sale to Investments held-to-maturity				$ 6,063,000,000